An arrangement for influencing and/or detecting magnetic particles in a region of action is known from German patent application DE 101 51 778 A1. In the arrangement described in that publication, first of all a magnetic selection field having a spatial distribution of the magnetic field strength is generated such that a first sub-zone having a relatively low magnetic field strength and a second sub-zone having a relatively high magnetic field strength are formed in the examination zone. The position in space of the sub-zones in the examination zone is then shifted, so that the magnetization of the particles in the examination zone changes locally. Signals are recorded which are dependent on the magnetization in the examination zone, which magnetization has been influenced by the shift in the position in space of the sub-zones, and information concerning the spatial distribution of the magnetic particles in the examination zone is extracted from these signals, so that an image of the examination zone can be formed. Such an arrangement has the advantage that it can be used to examine arbitrary examination objects—e.g. human bodies—in a non-destructive manner and without causing any damage and with a high spatial resolution, both close to the surface and remote from the surface of the examination object.
A similar arrangement and method is known from Gleich, B. and Weizenecker, J. (2005), “Tomographic imaging using the nonlinear response of magnetic particles” in nature, vol. 435, pp. 1214-1217. The arrangement and method for magnetic particle imaging (MPI) described in that publication takes advantage of the non-linear magnetization curve of small magnetic particles.
Arrangements and methods for magnetic resonance imaging (MRI) are widely known in the art. MR imaging has become one of the main imaging modalities, in particular in the medical field, and the details of the general layout of and MR system and the standard methods for MR imaging are described in many publications and standard books.
A combination of MPI and MRI would be very useful for a clinical acceptance of MPI. An MRI scan could be useful for planning the MPI examination or for identifying tissue parameters that are not accessible my MPI alone. For some patients, the scanner may be used as a pure MRI scanner if no MPI examination is scheduled.